A magneto-optical head includes an optical member, objective lens, SIL and coil. The magneto-optical head converts a laser beam to an evanescent light and directs it to a magneto-optical recording medium. Further, the magneto-optical head applies a magnetic field to the magneto-optical recording medium. When tilt is caused, it decreases the tilt angle. The optical member refracts the laser beam to a prescribed direction to be directed to the objective lens when the laser beam is displaced from a designed optical axis. The objective lens allows the laser beam to be focused onto a point on an end face of the SIL. Further, the SIL emits the evanescent light. The optical member is arranged in contact with the optical member. As a result, a signal can accurately be recorded or reproduced even when tilt is caused to an optical disk while alleviating the problem associated with the tilt.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A magneto-optical head recording and/or reproducing a signal to/from a magneto-optical recording medium by a laser beam and a magnetic field, comprising: a first lens having an end face opposite to said magneto-optical recording medium, converting said laser beam to an evanescent light and directing said evanescent light from said end face to said magneto-optical recording medium; a second lens fixed to said first lens for collecting said laser beam at an intersecting point of an optical axis of said first lens and said end face;and an optical member fixed to said second lens for refracting said laser beam toward a direction in which an optical axis of said laser beam comes closer to an optical axis of said second lens in accordance with tilt caused to said magneto-optical recording medium.
2. The magneto-optical head according to claim 1, further comprising a coil wound around said first lens.
3. The magneto-optical head according to claim 1, wherein said first lens is a solid immersion lens.
4. The magneto-optical head according to claim 1, wherein said optical member is in contact with said second lens.
5. The magneto-optical head according to claim 4, wherein said optical member includes a first member provided on said incident side and having a hole at a center, and a second member provided on said emitting side.
6. The magneto-optical head according to claim 5, wherein said second member includes SiN having a refractive index of 1.9 to 2.1.
7. The magneto-optical head according to claim 5, wherein said second member essentially consists of diamond.
8. The magneto-optical head according to claim 5, wherein said second member includes a first sub-member provided on said incident side and having a refractive index of 1.9 to 2.1, and a second sub-member provided on said emitting side and having a refractive index of 2.4 to 2.6.
9. The magneto-optical head according to claim 4, wherein said optical member has a refractive index increasing from an incident side to an emitting side for said laser beam.
10. The magneto-optical head according to claim 9, wherein said optical member includes a first member provided on said incident side and having a first refractive index, a second member provided closer to said emitting side than said first member and having a second refractive index higher than said first refractive index, and a third member provided on said emitting side and having a third refractive index higher than said second refractive index.
11. The magneto-optical head according to claim 10, wherein said first refractive index is 1.45 to 1.55, said second refractive index is 1.9 to 2.1 and said third refractive index is 2.4 to 2.6.
12. The magneto-optical head according to claim 9, wherein said optical member includes a first member provided on said incident side and having a first refractive index, and a second member provided on said emitting side and having a second refractive index higher than said first refractive index.
13. The magneto-optical head according to claim 12, wherein said first refractive index is 1.45 to 1.55 and said second refractive index is 1.9 to 2.1.
14. The magneto-optical head according to claim 12, wherein said first refractive index is 1.45 to 1.55 and said second refractive index is 2.4 to 2.6.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
September 22, 1999
October 2, 2001
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